Circulus de Potentia

Alex is still stuck in an alternate reality where Latin and math combine to make magic. The council is holding a festival in Nosaj’s honor, though Alex knows her whole group of friends should be celebrated for their efforts that concluded the first book. Begrudgingly, she attends the event, and is surprised to find it interrupted by a man wearing a circlet on his head with the symbol for pi on its band. He challenges Nosaj, but his uncle, Councilman Etan, offers up the Guardians in the hopes that one of them can defeat him and save Nosaj. After the challenger easily defeats several Guardians, it is understood the power of the gods rests in him from the circlet. The councilmen approach Archimedes, Alex’s teacher in this strange world and math genius, to solve the value for pi and stop the attacker, but he knows he must have help, so sends Alex and her new friends off to find Pythagoras. Archimedes believes that Pythagoras holds a secret that may unlock pi and save Nosaj, but time is running out, and there are many obstacles and dangers to overcome on the journey, including wolves, tribesmen, and monsters of Greek myths.

West has created a world in which math is a powerful tool, and its understanding is a magic in and of itself. It is no accident our main character is a girl, and he makes her all too real as she struggles to solve puzzles and help others. Her wavering confidence in her skills may inspire girls who struggle with math, and vindicate girls who excel in a male-dominated world. While this book is exciting, fast-paced, and a joy on its own, interested readers should treat themselves to the first book in the series, Libellus de Numeros, before becoming engrossed in the second.